Sprint Filter P08 F1-85 Air Filter for Racing – Yamaha XSR 900 (2015–2020) PM149S F1-85

Most XSR 900s of this generation have been altered somehow, and the changes tend to arrive in the same order: exhaust first, because it can be heard, then a calibration to suit it, and only afterwards does anybody ask what the engine breathes in. That order matters before buying the Sprint Filter PM149S F1-85, because it decides what the part can contribute. This is the racing medium — dry polyester filtering at 85 microns with a rated 15,000 l/m²/sec — and it is the last item on a list whose earlier items have already spent most of the available room.

Key Features

• Dry polyester racing weave with a filtration figure of 85 microns
• Rated 15,000 l/m²/sec against 5,050 for the P08 in the same airbox
• Retention measured by Sprint Filter at 95.22 per cent for 100-micron particles
• Direct replacement for the original element; the airbox is untouched
• Restored with compressed air, no oil used and none needed
• Two years of warranty from purchase, and a life expectancy tied to the bike

Where the filter belongs on the list

Intake restriction is shared across the whole path: the ducts, the airbox volume, the throttle bodies, and then the element. The element is the smallest share of it and the only one sold as a service part, which is precisely why it gets bought first by people hoping to feel something and last by those who have already done the rest. A standard 2015 to 2020 XSR 900 with everything else in place will not feel different with a freer element in the box — the deduction being reduced is not the one limiting the engine. On a bike whose exhaust and calibration are already done, it is a small consistency rather than a discovery.

What the racing medium gives and takes

It gives flow, close to three times the rated figure of the P08 from the same housing. It takes the fine end of the filtration, moving from 80 microns to 85 — and unlike the flow, which only counts near the top of the rev range, that applies every second the engine turns. Large-particle retention is the surprise: 95.22 per cent against the P08's 93.13 at 100 microns, so the coarser element is not simply worse. It costs about two and a half times the P08. The medium suits closed-circuit riding, where the air is swept and the element is cleaned between sessions; for a road bike of this age the P08 remains the sensible one.

Care and cleaning

Feed compressed air into the clean side and let the dirt leave through the face that caught it; that is the only routine service it needs. Where a deposit resists, lukewarm water and mild detergent do the rest, followed by a rinse and drying in moving air until the medium is dry throughout. Heat and flame are never used, and it is refitted dry and unoiled. The Sprint Filter maintenance sheet for the PM149S F1-85 is in the Downloads tab.

Fitment & Compatibility

Catalogued for the Yamaha XSR 900 built from 2015 to 2020 and fitted in the unmodified series airbox. The racing medium is listed for the XSR 900 alone, while the P08 version of this housing covers several further models of the generation; the Fitment tab has them.